route: move lwtunnel state to dst_entry

Currently, the lwtunnel state resides in per-protocol data. This is
a problem if we encapsulate ipv6 traffic in an ipv4 tunnel (or vice versa).
The xmit function of the tunnel does not know whether the packet has been
routed to it by ipv4 or ipv6, yet it needs the lwtstate data. Moving the
lwtstate data to dst_entry makes such inter-protocol tunneling possible.

As a bonus, this brings a nice diffstat.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 14 insertions, 21 deletions

diff --git a/net/ipv6/ila.c b/net/ipv6/ila.c
index 2540ab4..f011c3d 100644
--- a/net/ipv6/ila.c
+++ b/net/ipv6/ila.c
@@ -89,16 +89,13 @@ static void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
 static int ila_output(struct sock *sk, struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct rt6_info *rt6 = NULL;
 
 	if (skb->protocol != htons(ETH_P_IPV6))
 		goto drop;
 
-	rt6 = (struct rt6_info *)dst;
+	update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
 
-	update_ipv6_locator(skb, ila_params_lwtunnel(rt6->rt6i_lwtstate));
-
-	return rt6->rt6i_lwtstate->orig_output(sk, skb);
+	return dst->lwtstate->orig_output(sk, skb);
 
 drop:
 	kfree_skb(skb);
@@ -108,16 +105,13 @@ drop:
 static int ila_input(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct rt6_info *rt6 = NULL;
 
 	if (skb->protocol != htons(ETH_P_IPV6))
 		goto drop;
 
-	rt6 = (struct rt6_info *)dst;
-
-	update_ipv6_locator(skb, ila_params_lwtunnel(rt6->rt6i_lwtstate));
+	update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
 
-	return rt6->rt6i_lwtstate->orig_input(skb);
+	return dst->lwtstate->orig_input(skb);
 
 drop:
 	kfree_skb(skb);
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 5693b5e..865e777 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -178,7 +178,6 @@ static void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
 static void rt6_release(struct rt6_info *rt)
 {
 	if (atomic_dec_and_test(&rt->rt6i_ref)) {
-		lwtstate_put(rt->rt6i_lwtstate);
 		rt6_free_pcpu(rt);
 		dst_free(&rt->dst);
 	}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c373304..e6bbcde 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1784,14 +1784,14 @@ int ip6_route_add(struct fib6_config *cfg)
 					   cfg->fc_encap, &lwtstate);
 		if (err)
 			goto out;
-		rt->rt6i_lwtstate = lwtstate_get(lwtstate);
-		if (lwtunnel_output_redirect(rt->rt6i_lwtstate)) {
-			rt->rt6i_lwtstate->orig_output = rt->dst.output;
-			rt->dst.output = lwtunnel_output6;
+		rt->dst.lwtstate = lwtstate_get(lwtstate);
+		if (lwtunnel_output_redirect(rt->dst.lwtstate)) {
+			rt->dst.lwtstate->orig_output = rt->dst.output;
+			rt->dst.output = lwtunnel_output;
 		}
-		if (lwtunnel_input_redirect(rt->rt6i_lwtstate)) {
-			rt->rt6i_lwtstate->orig_input = rt->dst.input;
-			rt->dst.input = lwtunnel_input6;
+		if (lwtunnel_input_redirect(rt->dst.lwtstate)) {
+			rt->dst.lwtstate->orig_input = rt->dst.input;
+			rt->dst.input = lwtunnel_input;
 		}
 	}
 
@@ -2174,7 +2174,7 @@ static void ip6_rt_copy_init(struct rt6_info *rt, struct rt6_info *ort)
 #endif
 	rt->rt6i_prefsrc = ort->rt6i_prefsrc;
 	rt->rt6i_table = ort->rt6i_table;
-	rt->rt6i_lwtstate = lwtstate_get(ort->rt6i_lwtstate);
+	rt->dst.lwtstate = lwtstate_get(ort->dst.lwtstate);
 }
 
 #ifdef CONFIG_IPV6_ROUTE_INFO
@@ -2838,7 +2838,7 @@ static inline size_t rt6_nlmsg_size(struct rt6_info *rt)
 	       + nla_total_size(sizeof(struct rta_cacheinfo))
 	       + nla_total_size(TCP_CA_NAME_MAX) /* RTAX_CC_ALGO */
 	       + nla_total_size(1) /* RTA_PREF */
-	       + lwtunnel_get_encap_size(rt->rt6i_lwtstate);
+	       + lwtunnel_get_encap_size(rt->dst.lwtstate);
 }
 
 static int rt6_fill_node(struct net *net,
@@ -2991,7 +2991,7 @@ static int rt6_fill_node(struct net *net,
 	if (nla_put_u8(skb, RTA_PREF, IPV6_EXTRACT_PREF(rt->rt6i_flags)))
 		goto nla_put_failure;
 
-	lwtunnel_fill_encap(skb, rt->rt6i_lwtstate);
+	lwtunnel_fill_encap(skb, rt->dst.lwtstate);
 
 	nlmsg_end(skb, nlh);
 	return 0;